The present invention relates to high temperature superconductor systems and processes for making same.
A variety of superconducting systems have been created. In particular, several systems are based on thallium (Tl), including Tl-Ba-Cu-O, Tl-Sr-Ba-Cu-O, and Tl-Ca-Ba-Cu-O. For example, U.S. patent application Ser. No. 144,114, filed on Jan. 15, 1988 in the names of Z. Z. Sheng and A. M. Hermann, discloses Tl-Ba-Cu-O superconductor systems and processes for making them. This 90 K system is the first non-rare earth superconducting system above liquid nitrogen temperature.
In addition, U.S. patent application Ser. No. 155,247, filed on Feb. 12, 1988 in the names of Sheng and Hermann, discloses Tl-Ca-Ba-Cu-O and Tl-Sr-Ba-Cu-O superconductor systems and processes of making same. The addition of Ca into the Tl-Ba-Cu-O system resulted in superconductivity in excess of 120 K, the highest reproducible Tc to date.
Although superconducting systems disclosed in the above-identified patent applications have produced high-temperature superconductors and processes for making same, new systems are desirable for several reasons. A new superconducting system could:
1) Facilitate the discovery of the correct theory on oxide superconductivity; PA1 2) Extend the framework of the search for higher-temperature superconductors; and
3) Provide low cost processing and manufacturability.